I am trying to use GIMP (2.8.10) to make some indistinct annotations on a medieval manuscript more legible. Typical of the published images of its pages is
http://ica.themorgan.org/manuscript/page/35/159535

Examples of the scrawled additions I am trying to enhance are those in brownish ink after the end of the main (blackletter) text, and across the foot of the page.

So far I have tried Unsharp Mask (including varying the parameter settings); several of the colour adjustment tools (including the interesting but drastic Auto > Equalise); and Rob A's high-pass filter. All of these are some help, but I'm still looking for something better - and as a relatively inexperienced Gimp user, I'm concerned that I don't have a good enough understanding of the problem to pick the right tools.

Can anyone help, please? I would be really grateful for any and all suggestions.

Thanks, Alan

PS Ideally we could do with higher-resolution images to begin with, but as I don't have access to the original manuscript I have to work with those available on the web.

I do not think there are any "right tools" for this. Experimenting as you have done, is a good way to learn about Gimp.

If the same as I downloaded (about 400 x 600 pix) then really..a bit too small.

You could try:

1. Select the areas required. I used quick mask but freeselect in add mode works as well. see screenshot 1

2. With the selection active (toggle quickmask off) use the gmic plugin www.gmic.eu and the repair scanned documents filter. Output typical settings and output mode shown screenshot 2

3. Gives this with when selection is turned off screenshot 3

4. Put the new layer into Multiply mode to merge, gives as screenshot 4 but back to small image size and pixel sized graphics.

Using Gimp 2.8.10? Why, when the most recent stable is Gimp 2.8.22

rich: gimp-forum.net